Open the
options menuGo to the
Audio tab

Make sure "
Play Music" is checked on
Verify that your volume sliders are not at 0 or very low
Go to the
Network tab

Check on "
Download Music"
If that doesn't work, verify that your blockland sound is up on the windows volume mixer,
go down to the speaker icon in your system tray

Click "
Open Volume Mixer"

Verify that the "blockland" column is not at 0